Technical Field
The present disclosure relates to an integrated electronic device comprising a temperature transducer. In addition, the present disclosure regards a method for determining an estimate of a difference of temperature.
Description of the Related Art
As is known, today there exist semiconductor devices that each include an electronic component and at least one temperature transducer, which enables detection of a gradient (i.e., a difference) of temperature between two different points of the semiconductor device. In this way, during use of the electronic component, it is possible to determine whether it is necessary to implement strategies that prevent any damage to the semiconductor device.
For instance, illustrated in FIG. 1 are a temperature transducer 1 and an electronic component 3, which form an integrated electronic device 6; for example, the electronic component 3 is a power MOSFET.
The temperature transducer 1 includes a first diode 2 and a second diode 4, which are formed within a die 5, formed inside which is the integrated electronic device 6.
The first and second diodes 2, 4 may be of polysilicon. For instance, as illustrated in FIG. 2, the die 5 includes an epitaxial region 8, for example of an N type, extending on which is a body region 10, for example of a P type. Extending on the body region 10 is a dielectric region 12, made for example of thermal oxide. This having been said, the first diode 2 is formed by a first anode region 16, of polysilicon and with doping of a P+ type, and by a first cathode region 18, of polysilicon and with doping of an N+ type. The first anode region 16 and the first cathode region 18 extend on the dielectric region 12. A top region 20, made for example of a phosphosilicate glass, extends on the dielectric region 12 and part of the first diode 2. An anode metallization 22 and a cathode metallization 24 extend through the top region 20 for contacting the first anode region 16 and the first cathode region 18, respectively.
As illustrated in FIG. 1, the second diode 4 is formed by a second anode region 26 and by a second cathode region 28. Furthermore, the first and second anode regions 16, 26 are electrically connected, respectively, to a first pad 30 and a second pad 32 of conductive material, whereas the first and second cathode regions 18, 28 are electrically connected to a third pad 34. In addition, the first diode 2 is arranged within the active area 37 of the electronic component 3, i.e., in a central area of the die 5, whereas the second diode 4 is arranged in the proximity of an edge 40 of the die 5, i.e., in a peripheral area of the die 5, outside the active area 37. By way of example, FIG. 1 likewise shows a so-called “gate pad” 41 of the electronic component 3, as well as the so-called “gate finger” 43. Further, the electrical connections between the first and second diodes 2, 4 and the first, second, and third pads 30, 32, 34 are illustrated qualitatively. FIG. 3 shows, instead, an equivalent electrical diagram of the temperature transducer 1.
In use, the first, second, and third pads 30, 32, 34 may be electrically connected to a controller (not illustrated) designed to inject in the first and second pads 30, 32 a first current IH and a second current Ic respectively. The controller is thus designed to forward bias the first and second diodes 2, 4. In addition, the controller collects on the third pad 34, a current equal to IH+IC. In addition, albeit not illustrated, the controller is electrically coupled to the first and second diodes 2, 4 for detecting a first voltage VF1, across the first diode 2, and a second voltage VF2, across the second diode 4. Assuming that the first and second diodes 2, 4 operate in the proximity of the respective threshold voltages, each of the first and second voltages VF1, VF2 decreases by approximately 2 mV per degree centigrade.
Since the first and second voltages VF1, VF2 depend upon the temperature of the first and second diodes 2, 4, respectively, the controller may detect onset of situations that are potentially dangerous for operation of the electronic component 3, on the basis of the first and second voltages VF1, VF2. In particular, assuming, for example, that the integrated electronic device 6 is shorted, there is a rapid increase in temperature of the first diode 2, while the temperature of the second diode 4 increases more slowly. A difference is thus created between the temperatures of the first and second diodes 2, 4, which tends to increase over time. In other words, a temperature gradient presents within the die 5 and may be detected by the controller, on the basis of the first and second voltages VF1, VF2. Once an anomalous condition of use of the electronic component 3 is detected, the controller may co-operate with the driving circuit (not illustrated) of the electronic component 3 in order to implement a technique of protection or the electronic component 3. For example, it is possible for the electronic component 3 to be turned off.
In practice, the temperature transducer 1 transduces a difference of temperature into a voltage difference. In this connection, it is possible to show that detection of a temperature gradient, instead of detection of the absolute temperature of a single point of the integrated electronic device 6, enables reduction of the time that elapses between onset of an anomalous condition of use of the electronic component 3 and subsequent implementation of a protection technique. However, the temperature transducer 1 requires three pads, and thus entails a certain consumption of area of the die 5.